Red ones of heating block.for tubing - About 14 inch long. Due to high lubricity and high-temperature resistance, it improves the printing quality and accuracy.Pluggable: the heating tube and temperature thermistor that from control box, connect with terminal housing and pin. Then you could plug the hotend kit, easier to replace hotend kit.With more terminal housing and pins as spare parts, in case fail installation and waste .MK8 Extruder Hot End kit, white wire temperature thermistor, braided wire heating tube 24V40W.Product Name: CR10 hotend kitNozzle: 1.75 or 0.4mmthroat hole:4.1Thermistor:100K NTC B 3950 1 percent ,length 1 mHeating Tube: 24V 40W 1mThroat length: 30mm tube:ID2 OD4mm 1mInstallation Type: External Thread ConnectionOperating temperature range: -40-and260C (-40-and500F)Features: and high quality.Notes:(About gift Silicone Cover, we have four colors :Blue, Yellow,Black and Brown, shipped randomly, .)24V 40W is speacially designed for CR10 Series and 3 series products.Pls the products according to your .size:30mmMaterial:aluminumcolour:RedPackage Contents:1 x Extrude Hot End KitOnly the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is 1-3cm.